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By P. K. Koh

Isothermal salt bath annealing of 0.014-in. thick 3 pct Si-Fe sheet was conducted at temperatures ranging from 927" to 1260°C in order to investigate the grain-growth behavior. Within the temperature range studied normal grain growth did not take place; instead nucleated grain growth prevailed. The nucleation frequency was found to increase with the annealing temperature, with corresponding decrease in grain diameter of ultimate secondaries after long-time annealing. Large secondaries grown by low-temperature isothermal annealing are essentially of (110)[001] orientation, and the (110)[001] texture is strong. The relatively small secondaries grown by high-temperature isothermal annealing also have orientations near (110)[001] as an average but widely scattered; thus the amount of (110)[001] texture is found to decxease with isothermal annealing temperature. Grain growth and texture development at various annealing temperatures can be described by families of sigmoidal curves with the time axis. ThE cube-on-edge (110)[001] texture and predominating large secondaries in fully annealed 3 pct Si-Fe are customarily produced by a 1100°C annealing of a primary recrystallized sheet. On annealing the primary recrystallized sheet above the temperature at which secondary recrystalliza-tion starts May and turnbull' have demonstrated that secondary grains decrease in size as the temperature is increased. The phenomenon was attributed to a decrease in the (G/N) ratio where G is the growth rate of secondary grains and N is their nucleation frequency. In addition, the growth of grains in orientations rather far from (110) [0011 occurred. The present investigation is devoted to detailed rate studies of the same phenomenon. Mi-crostructure, magnetic anisotropy, and texture data were obtained on strips of 3 pct Si-Fe isothermally annealed for various lengths of time in a BaC12 salt bath at temperatures ranging from 927' to 1260°C. The texture results are reported elsewhere.2 EXPERIMENTAL PROCEDURE Commercial 0.014-in. cold-rolled silicon-iron strip (3.16 pct Si), prepared by two stages of cold rolling with an intermediate short anneal, was given a decarburizing 3-min anneal at 800°C. Metallo- graphic studies indicated complete recrystallization. In order to provide a protective atmosphere and to obtain a rapid rise to an elevated temperature, a BaC12 and NaCl fused salt bath was used to heat samples isothermally at temperatures from 927" to 1260°C for various lengths of time. Torque magnetometer measurements were made on 1-in.-diam disc specimens before and after annealing, since magnetic torque curves supply information on textures and texture changes. Surface layers of the strip samples were polished and etched to reveal the grain structure. The diameters of grains were measured from micrographs at X100. The average value of diameters of matrix grains was established. Individual grains in the micrograph were cut out separately along grain boundaries. These grains were classified either as matrix grains or growth grains. The percent weight of growth grains in the cut-out patterns was reported as percent growth. Manv of the individual grains in the annealed samples were large enough to be X-rayed with a 5-mil beam for Lauegrams. Complete (110) pole figures were obtained for the primary recrystallized structure and short-time annealed structure with CoKa radiation at 30 kv in the back-reflection range, such as (220) for (110) poles, as described recently by Newkirk and ~ruce.~ Both the X-ray optics and the technique for pole figure differed slightly from those adapted previously.4

Jan 1, 1960

By E. W. McAllister

THE decision of the California Oil Umpire's1 office to accept well potentials established from subsurface-pressure data has brought to the attention of many operators for the first time the application of such data to production problems. This paper reviews the development and application of subsurface-pressure data in Kettleman Hills, where these data have been used in production work since 1932. The Kettleman Hills field was discovered in October 1928. The first subsurface-pressure surveys were made early in 1932 and by the middle of 1933 the two major operators in the field were making routine pressure runs in their respective wells. Shortly thereafter, these companies agreed to exchange pressure data, and later a third company entered into the agreement. This made it possible to analyze the effects upon the reservoir pressure of past production practices, which are discussed in the latter part of the report. It is interesting that many of the applications of subsurface-pressure data discussed herein were anticipated by C. L. Clarks and C. B. Kimberlin‡ in a reports dated March 1933. PRODUCTIVITY INDEX In the majority of individual well problems involving the use of subsurface pressure data, it is necessary to use a factor known as the "productivity index," which indicates the ability of a well to produce and represents the number of barrels of oil or oil and water per day that will enter the well bore for each pound per square inch pressure drop made opposite the producing interval of the well. The productivity index may be determined from pressure and production data for one or more rates of flow and a static or shut-in pressure survey or from production and pressure data for two or more rates of flow. Productivity indices may be based upon either net oil or total fluid production. All indices referred to in this report are based upon net oil. The value of the productivity index for Kettleman Hills wells decreases generally with time and it is not uncommon for the index to vary in value at any specific time for various rates of flow. The decline of the productivity index may be attributed partly to the loss of reservoir pressure. As. the reservoir pressure decreases, gas originally in solution is released from the oil, congesting the flow of fluids through the formation and increasing the viscosity and surface tension of the oil; thus the flow resistance of the fluids through the formation is increased, resulting in a decrease of the productivity index. For convenient reference, the productivity indices for each well are plotted against time and a curve is drawn through the points showing the trend of the average index value. Plotted on Fig. I are index values for five

Jan 1, 1941

By Robert Glass Cleland

BECAUSE of the country's vast mineral resources, Alexander Von Humboldt, the great German scientist who visited Mexico, or the Kingdom of New Spain, a hundred and fifty years ago, very aptly called that country the "Treasure Chest of the World." During the three centuries of Spanish rule, mining was the principal industry of the kingdom, the largest contributor to the country's prosperity, the chief common denominator in Mexican economic life. Public revenues and private fortunes, employment and markets, agriculture and trade, charities and churches, the incentive for frontier settlement and exploration, and the funds for outfitting the expedition of colonizer and conquistador-all were dependent upon the streams of precious metals that flowed century after century from the mines of Guanajuato, Zacatecas, Real del Monte, San Luis Potosi, and scores of other minería that lay scattered everywhere throughout the land. Sonora, one of the oldest and most renowned of the frontier provinces of New Spain, had been the scene of a hundred rich strikes, sudden stampedes, and widely heralded bonanzas long before the famous and frenzied Gold Rush

Jan 1, 1952

By AIME AIME

CONVENTION plans for the A.I.M.E. Regional Meeting to be held on the Minnesota Iron Range Aug. 12 to 1.5 are being completed to give the visiting member?s from all parts of the country a wide variety of technical and recreational features. High spots of the social events are the official dinner, dance, luncheon and golf: and of course, special provision is being, made for the entertainment of visiting ladies. The technical sessions will fit in with scheduled trips to view all phases of mining, beneficiation and transportation of iron ore. Men from the West and Southwest will find much of interest in the detail of the mining operations. A trip to the steel plant of the

Jan 1, 1941

By D. W. Loughridge

INTRODUCTION Raising capital in the 1990s is a timely subject. However, many of us thought why should raising capital in the 1990s prove to be unlike it was in the 19805, the 1970s, the 1%0s, or earlier? There are a lot of creative people in banking and in corporate treasury departments. New tools and techniques are continuing to emerge, many of which are discussed in other papers in this book. While we have new financing tools at our disposal, the underlying issue has not changed. Projects and investments must be judged on their own merits. If they cannot be justified by conventional financial analysis, they should not be built. If they can be justified, it is likely that the financing will be available. The challenges faced in raising capital in this decade will persist to the next. The issues of the 1980s -- currency fluctuation, disruptive merger and acquisition activity, commodity price volatility, political risk, and debt crisis -- will all persist in an increasingly international business environment. I will focus on the financing we have just completed for the Escondida Copper Project in Chile. The Escondida financing is structured along the classic project financing model developed in the late 1970s, but it deals with issues of the 1980s and the 1990s. The financing was intriguing, not just because of the technical issues involved, but also the challenge of reaching an agreement in a large and diverse group. Escondida had the one essential feature that made its financing possible. It was commercially very attractive. It would produce at low cost a commodity (copper concentrates) that direct consumers felt would be in tight supply. The project had the direct support not only of its sponsors, but also its customers, and, very importantly, its host government. The non- recourse financing of Escondida would not have been possible without the support of these parties, and without the robust economics that made this effort worthwhile. The issue was more complicated. Operations in all parts of the world entail some political exposure. This project is in Chile, where there was a constitutional requirement that a plebescite be held when the project would be in its early stages. This plebescite would determine the fate of a 15 year old military dictatorship. The project is copper, a commodity generally deemed to be in surplus. Copper has a history of price volatility (whose price has varied from $.58 to $1.53 per pound over the past two years). It is politically sensitive, not only in Chile, but in the United States, Canada and other developed countries. The project is international, with all the problems of dealing with a variety of currencies, a variety of cultures, and a variety of laws and commercial practices. The project is also large and capital intensive, with a total cost of U.S. $1.1 billion. ESCONDIDA PROJECT Escondida, the largest known copper ore body in the world, was discovered in March of 1981, by Utah International in a joint venture with Getty Oil Company. In 1984, both Utah and Getty were involved in ownership changes, Utah being acquired by BHP. A later restructuring of the ownership of Escondida resulted in BHP, as manager, carrying a 60% interest, Rio Tinto-Zinc Corporation (RTZ) 30%, and a consortium of Japanese companies led by Mitsubishi Corporation with 10%. The Japanese consortium is incorporated as JECO (Japan Escondida Corporation). This ownership structure, which spread ownership around the world, was the first tangible step toward managing both the commercial and political risk associated with the project.

Jan 1, 1990

By A. Faison Dixon

In India the production of mica, which in other countries is of very minor importance, is one of the staple, long established industries, and ranks high in the statistics of mineral products. Nearly two-thirds of the mica of commerce comes from India. The Indians have used mica for glazing and decorative purposes through many centuries. About 14,000 men are employed in and about the mines, and the indigenous and primitive mode of mining is still followed; but, by reason of the exhaustion of the surface supply hitherto won without intelligence or capital, it will not be many years before the present interesting and casual methods will be replaced by a less archaic and more profitable system. India on the whole has little mineral wealth, but the unique resources of its mica-fields, cheap labor, and favorable natural conditions render it unlikely that any other country can ever more than temporarily contest her leadership in the production of this one minor but essential mineral. Mica plays a small but indispensable rôle in a variety of fields of dissimilar application. Its use and value depend upon characteristics which different kinds of mica have in varying degrees, each kind being adapted to its own special purpose. Its well-known characteristics of transparency, flexibility, elasticity, toughness, high dialectric strength, perfect flatness, ease of splitting into thin films, ability to stand high heat and sudden changes in temperature, give it value in many industries. No other substance, natural or artificial, has the same combination of qualities. The oldest use of mica is in glazing. By reason of the improvements in annealing glass, this is not now of great importance, but mica is still employed for the covers of ikon images in Russian churches, the windows of anthracite stoves, compass

Jan 1, 1914

By C. H. Mathewson, H. M. Day

The constitution of the system silver-mercury has attracted the attention of many investigators during the last two decades, but since their results are for the most part in poor agreement, there is little need for a review of their individual contributions. It remained for the very careful thermal and microscopic investigation of Murphy1 in 1931 to give the constitutional diagram in its present and unquestioned form, which is shown in Fig. 1. He devised methods for taking cooling curves on alloys under high pressures and for the microscopic observation of alloys which contained liquid mercury as a structural constituent at ordinary temperatures. The compositions of the intermediate phases were confirmed and supplemented through X-ray analyses by Preston2 and Stenbeck.3 According to Murphy, at 2760 C. silver is able to dissolve 44 to 45 weight per cent of mercury, which may increase at lower temperatures to about 50 per cent. Preston concluded that the saturation boundary occurred at 46 ± 2 per cent at 100° C. From the values reported in the literature, these are the only ones that may be accepted as lying even in the right region. Preparation of Alloys The silver used in the present investigation was supplied by the United States Metals Refining Co. through the courtesy of the Committee on Industrial Uses of Silver and, since a complete spectrographic and chemical analysis was furnished, no attempt was made to purify it or to further establish the impurities present. The analyses reported by the company are shown in Table 1. Milligan4 has found that the magnesium content is probably less than 0.0005 per cent.

Jan 1, 1938

By H. M. Day, C. H. Mathewson

The constitution of the system silver-mercury has attracted the attention of many investigators during the last two decades, but since their results are for the most part in poor agreement, there is little need for a review of their individual contributions. It remained for the very careful thermal and microscopic investigation of Murphy1 in 1931 to give the constitutional diagram in its present and unquestioned form, which is shown in Fig. 1. He devised methods for taking cooling curves on alloys under high pressures and for the microscopic observation of alloys which contained liquid mercury as a structural constituent at ordinary temperatures. The compositions of the intermediate phases were confirmed and supplemented through X-ray analyses by Preston2 and Stenbeck.3 According to Murphy, at 2760 C. silver is able to dissolve 44 to 45 weight per cent of mercury, which may increase at lower temperatures to about 50 per cent. Preston concluded that the saturation boundary occurred at 46 ± 2 per cent at 100° C. From the values reported in the literature, these are the only ones that may be accepted as lying even in the right region. Preparation of Alloys The silver used in the present investigation was supplied by the United States Metals Refining Co. through the courtesy of the Committee on Industrial Uses of Silver and, since a complete spectrographic and chemical analysis was furnished, no attempt was made to purify it or to further establish the impurities present. The analyses reported by the company are shown in Table 1. Milligan4 has found that the magnesium content is probably less than 0.0005 per cent.

Jan 1, 1938

By Edward B. Durham

At the Richmond mecting in February, 1901, I presented for discussion the proposed rail-specifications of Committee No. 1 of the American Section of the International Association for Testing Materials, with a review of their work, and other matters relating to the heat-treatment and chemical composition of steel (Trans., xxxi., 455). In order to bring out the views of our members on the important points referred to, I offered for discussion the following questions and comments (trans., xxxi., 972): " 1. The advantages to be gained by using more metal in the flanges and web of the heavier sections of rails.

Jan 1, 1903

By B. G. Klugh

(New York Meeting, February, 1913.) THE present paper represents a preliminary investigation of the ultimate structure of iron-bearing materials which have been subjected to heat treatment for the purpose of agglormer-ating the fines, or for chemical changes, or for both. Primarily, the object of this inquiry was to determine the relation of the microstructure of each of these materials-to its specific susceptibility to the action in the blast-furnace. It is hoped that this small contribution will serve as a nucleus to a line of research that will throw some light upon the debated questions involved in blast-roasting. Thus far the investigation has been conducted along lines of analogy of known principles, rather than through the applica-tion of any well-defined system of microscopic petrography. This is obviously due to the fact that we are dealing with materials which are the artificial products of a new art, rather than with the natural materials from which the essence of the pure science has been evolved. In the limited tune allowed for this research, it has been conducted upon those materials the chemical content of which allows of their use commercially in the blast-furnace.

Jan 5, 1913

By Max Boehmer

(Pittsburg Meeting, March, 1910.) AFTER 30 years of development and after an output of $350,000,000 in value of gold, silver, lead, zinc, and copper, there has not been published a satisfactory explanation of the origin of the immense deposits of the Leadville district. The original examination find survey of Leadville by members of the U. S. Geological Survey was a most magnificent piece of work, but their attempt to explain the origin of the ores was based upon the then-accepted theory of lateral secretion, originated by Sandberger, which theory was afterwards disproved in many cases by further development in numerous districts. This theory contended that the ore in the veins had been leached by surface-waters from the eruptive rocks in the immediate vicinity, and it had its origin in the fact that the neighboring eruptive rocks all contained, to an appreciable degree, the several metals found in the ore-deposits. But the practical miner, reasoning in a simple manner from the condition of things as he found them underground, soon discovered the fallacy of this proposition. He reasoned that, in the case of the Leadville deposits, this theory could not be true, because, if the ores were leached from the overlying eruptive rocks by surface-waters, they would as a matter of necessity be controlled by the action of gravity, and the main bodies would collect in- natural depressions of the underlying limestone, and at all points where such depressions existed. But this was not in accord with the channels of ore as he found there ; and hence the theory of lateral secretion in this district was never accepted. Another objection to it consisted in the fact that large areas within the ore-bearing district contained no ores whatever, although their formation was the same, and the same limestones were covered by the same thick sheet of

Feb 1, 1910

By B. J. Kochanowsky

TO improve blasting methods it is necessary to know how the explosive force acts and how rock resists this force. Because of the tremendous power developed within milliseconds and the great number of other factors directly affecting the technical and economic results, an analysis of the fundamentals of blasting theory is difficult. But since the rules used for layout design and for calculations of size of explosive charges are based on theoretical assumptions, complete knowledge of blasting theory has great practical importance in mining. Analysis of Blasting Theory: It is interesting to note the opinion of blasting experts with respect to contemporary blasting theories. F. Stussi; Professor of the University of Zurich, stated: "We do not have enough experience yet to change our army engineering regulations in blasting and base it on new fundamentals. It is our duty to collect more practical data and to do more research in blasting to close this gap." K. H. Fraenkel,2 editor of the Manual on Rock Blasting published in 1953 in Sweden and written by well-known Swedish, German, Swiss, and French blasting and explosive experts, said: "To the best of our knowledge no suitable formulas for civil blasting work are to be found in the American, French or German literature." Present blasting theory is based upon two assumptions. 1) The blasting force of explosive acts in concentrical and spherical form. 2) Rock resistance against the explosive force is directly proportional to the strength characteristics of the rock. The first classical formula based on theoretical fundamental in blasting theory for explosive charge calculation was introduced by Vauban, a military engineer who lived 300 years ago. It was Vauban who proposed the famous formula L = w3 q, where L is the explosive charge, w = line of least resistance, and q = specific explosive consumption proportional to the weight of rock. Later engineers used q as proportional to the strength of the rock. Since Vauban's time different suggestions concerning blasting theory have been proposed. However, the principles stated at that time so affected the thinking of later generations that his formula is still in use and practically unchanged. The first controversy concerned the form of crater. It was found that geological features of rock affected its form. The factor q was analyzed thoroughly by Lares3 and later by Ohnesorge," Weichelt,5 Bendel,6 and others, but the assumption remained that resistance against explosive force is directly proportional to the strength of the rock blasted. The greatest controversy, which has not yet been settled, concerned w. It was noted that w3 is more appropriate for long lines of resistance and w2 for lines of resistance less than 15 ft. Based on the assumption that the explosive force acts concentrically and spherically, spacings between charges were limited to distances not greater than the length of line of least resistance. Sometimes larger spacing is recommended, but this is due to the advantageous geological and physical properties of rock and not to the action of an explosive force as such. In addition to the classical formula, empirical formulas are used widely. These state that the explosive charge is directly proportional to the volume of blasted rock in cubic yards, and the amounts of explosive required are usually expressed in pounds of explosive per cubic yard of rock. Empirical and classical formulas are contradictory. In the empirical formula, but not in the classical formula, explosive charge is taken proportional to all three space axes: line of least resistance, spacing, and bench height. In spite of this contradiction, both formulas give good results. This is possible because as now practiced the explosive charge calculation for heavy burdens need not be highly accurate. Each, open pit or quarry, usually works with a certain relation between bench height and line of least resistance and between charge spacing and line of least resistance. When these relations are changed, however, the specific explosive consumption q changes greatly. This is one of the reasons why the principles on which the formulas are based appear to be incorrect. In addition to the formulas discussed, others exist and are based more or less on the same theoretical

Jan 1, 1956

By Emory J. Douglass

Mining companies are unique in that they extract mineral resources and must therefore deal with ecological disturbances and other special problems. Like most enterprises, however, their primary motive must be to make money. The problem of mining investment starts with the question of what "make money" means. This article proposes an answer consistent with what economists call the theory of the firm and then applies it to two of the common, and perhaps unrecognized, problems connected with min¬ing investment. In essence, the concepts presented here call for thinking to terms of the income change associated with a given change it outlays or operating procedures To illustrate. ABC Distributing Co. has just discovered the power of advertising. It has raised its annual advertising budget from $25,000 to $50,000, and sales have, zoomed from 250.000 to 350,000 units. The company buy, for 50e per unit and sells at $l. This move has produced $50,000 of operating income for $25.000 in additional advertising expense. This looks great, so the next year the advertising budget goes up to $100,000. Sales go to 440,000 units. With 90,000 more units at 50[c] per unit, ABC sales are up by $45.000. Its advertising costs, however, went up $50,000.

Jan 1, 1971

By Daniel Martin

THE dendritic pattern of steels shown by deep etching is used exten-sively as a guide in the inspection and control of the great majority of steels used in ordnance construction and for many applications in indus-try. The value of macroexamination lies in the fact that it enables a qualified observer to make deductions concerning the general quality of relatively large pieces of metal. Not the least of these general character-istics is the nature and extent of the dendritic segregation in the steel, either in the cast condition or after mechanical or thermal treatments. PREVIOUS WORK Detailed methods for macroetching were outlined by Yatsevitch1 and have been standardized by the American Society for Testing Materials. A comprehensive study of the occurrence, origin, and the chemical and crystalline nature of the dendritic structure was given by Keshian.2 The marked persistence of dendritic segregation in nickel steels is fully recognized and has been discussed by Sauveur and Reed' and by others. Very little, however, has been written on the effect of the various elements on the macrostructure of steels, and the purpose of this report is to submit evidence concerning the influence of chromium, nickel and molybdenum on the macrostructure of some 4 by 4-in. ingots cast and treated under closely controlled conditions.

Jan 1, 1939

By V. J. Driscoll

A method is given for checking pore volume reserve estimates and transient water inflzix factors utilizing early well performance. Principal applications are based on the observation that there is a convenient transient time-range in terms of well spacing in which observed pressure drop will give a good indication of fluid-in-place. Primary quantity determined is a porosity-feet value applicable in the vicinity of an observation well. Checks on porosity or net pay thickness and permeability values also are obtained. These are particularly valuable in improving quality of interpretive factors entering into pore-volume reserve determinations for larger fields. In smaller fields, direct determination of total field reserves and approximate location of boundaries may be made in some cases. Well interference and production data plus a build-up curve on the observation well are needed. The build-up curve may be taken at any time. Field applications are given. The method can be applied with the completion of the second well on a new discovery or to older reservoirs by major changes in withdrawal rates from a local area. Appropriate test length permits results to be obtained with equal accuracy on widely spaced wells. Criteria for optimizing test conditions are given. Provision is made for various boundary and well effects including incomplete observation well build-up. INTRODUCTION Due to low quality data, initial pore volume reserve and water influx estimates may often vary by a factor of two or more from results obtained at a later date. Unfortunately, by conventional methods, more reliable answers from performance usually are not available until after most significant economic decisions have been made. Furthermore, in older reservoirs, uncertainties may still exist as to original oil-in-place, recovery factors and residual oil saturations due to incomplete or inaccurate performance data. This paper outlines situations and appropriate arrangements of basic transient theory whereby well interference data can be utilized to improve the quality of estimates under certain conditions. In addition to production data on offset producers, key information required is a measured pressure drop at an observation well, corrected for any incomplete build-up due to previous production, plus a formation capacity value derived from a conventional pressure build-up plot on the observation well. The method, as outlined, is strictly applicable only to a horizontal single-layered system of uniform rock characteristics containing a homogeneous fluid of low and constant compressibility. However, under the set of test conditions devised, requirements can usually be relaxed so that it should be applicable to most low permeability gas, water and undersaturated oil reservoirs. This is an area where more reliable information is certainly needed. BASIC CONSIDERATIONS A, B, C and F as subscripts or in the text refer to producing Well A, observation Well B, a more remote producing Well C and field boundary F. Combinations such as AB refer to distances and dimensionless times in terms of distances between these points, while single letters refer to distances and dimensionless times in terms of the well-bore or field radius. Equations covering definitions of quantities and complex situations are given in the Appendix. Key equations in practical units are given in Table 2. Transient Pressure Behavior Fig. 1 illustrates pressure drop at Point B with time due to initiation of a constant rate of withdrawal from Point A. This is shown as since a quantitative under-

By Robert Steinitz

SOFT iron parts for magnetic applications, particularly pole shoes, constitute a major portion of the ferrous products of powder metallurgy. The residual pores in pressed and sintered parts reduce values such as the magnetic permeability but service experience extended over a number [ ] of years has proven beyond doubt that in many instances the lower density of powder parts is not prohibitive to their use m replacement of machined magnetic parts The. magnetic requirements for pole shoes particularly the permeability, vary within wide limits, especially with the relative size of the air gap in the finished assembly. The overall permeability of an assembly, µ, is given by the formula [ ] where µm is the permeability of the core material, l the total length of the magnetic path, and a the length of the air gap. Fig 1 shows the variation of the overall permeability with the permeability of the core material, calculated according to Eq I for an air gap of 1 pct of the total length of the magnetic circuit. It is readily recognized that to use core materials hav-

Jan 1, 1948

By Robert Steinitz

Soft iron parts for magnetic applications, particularly pole shoes, constitute a major portion of the ferrous products of powder metallurgy. The residual pores in pressed and sintered parts reduce values such as the magnetic permeability but service experience extended over a number of years has proven beyond doubt that in many instances the lower density of powder parts is not prohibitive to their use as replacement of machined magnetic parts. The magnetic requirements for pole shoes, particularly the permeability, vary within wide limits, especially with the relative size of the air gap in the finished assembly. The overill permeability of an assembly, is given by the formula where is the permeability of the core material, I the total length of the magnetic path, and a the length of the air gap. Fig I shows the variation of the overall permeability with the permeability of the core material, calculated according to Eq I for an air gap of I pct of the total length of the magnetic circuit. It is readily recognized that to use core materials hav- A

Jan 1, 1949

On the Art of Metallography (Howe Memorial Lecture), by F. F. Lucas; Beneficiation of Iron Ore. Abstract of paper by C. E. Williams followed by Round Table Discussion; A Statistical Analysis of Blast-furnace Data, by R. 8. McCaffery and R. G. Stephenson; Air Discharge of Circular Tuyeres, by R. S. McCaffery and D. E. Krause; Open-hearth Steel Process as a Problem in Chemical Kinetics. by E. R. Jette; Carbon-oxygen Equilibrium in Liquid Iron, by H. C. Vacher and E. H. Hamilton; A Thermodynamic Study of the Phasial Equilibria in the Bystem Iron-carbon (Abstract), by Yap, Chu-Phay; Influence of Dissolved Carbide on the Equilibria of the System Iron-carbon (Abstract), by Yap, Chu-Phay; Inclusions and Their Effect on Impact Strength of Steel, I and 11, by A. B. Kinzel and W. Crafts: Method for Electrolytic Extraction of MnO, MnS, FeS and Si02, Inclusions from Plain Carbon Steels, by G. R. Fitterer; Permanent Growth of Gray Cast Iron, by W. E. Remmers; Some Notes on Blue Brittleness, by L. R. van Wert; Austenite-pearlite Transformation and the Transition Constituents, by A. Sauveur; Age-hardening of Austenite, by F. R. Hensel; Transformational Characteristics of Iron-manganese Alloys, by H. Scott; Composition Limits of the Alpha-gamma Loop in the Iron-tungsten System, by W. P. Sykes; Magnetic Properties Versus AUotropic Transformations of Iron Alloys, by T. D. Yensen and N. A. Ziegler; Dilatometric Study of Chrome-nickel-iron Alloys, by V. N. Krivobok and M. Gensamer; Low-carbon Steel, by H. B. Pulsifer; Bright Annealing of Steels in Hydrogen, by F. C. KeUey; Development of Continuous Gas Carburieing, by R. J. Cowan. Transactions, Institute of Metals Division, 1931. 500 pages. Index. Papers and discussions presented before the Division at Chicago, Sept. 22-26, 1930 and New York, Feb. 16-19, 1931. X-ray MetallograpIhy: X-ray Determination of Alloy Equilibrium Diagrams (Annual Lecture), by A. F. Westgren; Suppressed Constitutional Changes in Alloys. by G. Sachs; Texture of Metals after Cold Deformation; by F. Wever. Theoretical Metallurgy: Studies upon the Widmanatitten Structure. I.—Introduction. The Aluminum-eilver System and the Copper-silicon System; by R. F. Mehl and C. S. Barrett; Studies upon the Widmanstatten Structure, 11.—The Beta Copper-einc Alloys and the Beta Copper-alumnum Alloys, by R. F. Mehl and 0. T. Mareke; Application of X-rays in the Manufacture of Telephone Apparatus, by M. Baeyerts; Thermal Conductivity of Copper Alloys. 11.—Copper-tin Alloys; 111.—Copper-phosphorus Alloys, by Cyril Stanley Smith; Thermodynamic Study of the Equilibria of the Systems Antimony-bismuth and Antimony-lead, by Yap, Chu-Phay. Ganeral: Cemented Tungsten Carbide; a Study of the Action of the Cementing Material, by L. L. Wyman and F. C. Kelley; Influence of Casting Practice on Physical Properties of Die Castings, by C. Pack; Fabrication of the Platinum Metals, by C. S. Sivil; Effect of Certain Alloying Elements on Structure and Hardness of Aluminum Bronze, by 9. F. Hermann and F. T. Sisco. The WorkinG oF Metals: Metal Working in Power Presses, by E. V. Crane; Forming Properties of Thin Sheets of Some Nonferrous Metals, by W. A. Straw, M. D. Helfrick and C. R. Fischrupp; Die Pressing of Braas and Copper Alloys, by J. R. Freeman. Jr.; Plasticity of Copper-sina Alloys at Elevated Temperatures. by A. Morris: Directional Properties in Cold-rolled and Annealed Copper, by A. Phillips and E. 9. Bunn; Effect of Combinations of Strain and Heat Treatment on Properties of Some Age-hardening Copper Alloys by W. C. Ellis and E. E. Schumacher; Constituents of Aluminum-iron-silicon Alloys, by W, L. Fink and K. R. Van Horn; Equilibrium Relations in Aluminum-antimony Alloys of High Purity, by E. H. Dix, Jr., F. KeUer and L. A. Willey; Equilibrium Relations in Aluminum-magnesium Silicide Alloys of High Purity, by E. H. Dix. Jr., F. Keller and R. W. Graham; Constitution of High-purity Aluminum-titanium Alloys, by W. L. Fink, K. R. Van Horn and P. M. Budge; Experiments on Retarding the Age-hardening of Duralumin, by E. H. Dix. Jr. and F. KeUer; Aluminum-silicon-magnesium Casting Alloys, by R. S. Archer and L. W. Kempf; Modulurr of Elasticity of Aluminum Alloys, by R. L. Templin and D. A. Paul; Quenching of Alclad Sheet in Oil, by H. C. Knerr.

Jan 1, 1931

By Frank T. Weems

The basic operating properties of the DorrClone are discussed and certain metallurgical applications which exploit these properties are presented. An effective method of controlling the consistency of the DorrClone underflow is described. THIS paper presents in a general manner some of the applications of the DorrClone (Dutch States Mines cyclone) in the metallurgical and heavy chemical fields. Technical or mathematical analyses of the design factors and of the mechanism whereby the cyclone effects its separation have been capably treated in a series of previous papers.'-' Engineering and operational aspects of a few installations and laboratory tests have been chosen to emphasize the unique classification characteristics of the DorrClone and to illustrate its utility in certain difficult situations. Its use in coal washing and heavy-media operations are not considered. Some 25 or more industrial installations and applications of the DorrClone in the metallurgical fields are operating at present, ranging from single trial units to complete batteries composed of a multiplicity of units. The data were obtained in part from some of these, and in part from operations of units at the Westport Mill, the laboratories and testing plant of the Dorr Co. at Westport, Conn. The DorrClone was developed, in principle, by the research dept. of the State Mines, Limburg, Holland, during World War 11. Its first use was to dewater a —50 micron sand used as a dense medium in coal washing. The metallurgical wet cyclone was first publicized by Driessen and Yancey and Geer.6 ince then the cyclone has been studied as a means of de-watering, heavy media concentration, and fine size classification. The DorrClone is shown in Figs. 1 and 2. pulp to be treated is pumped through the feed nozzle, A, into the feed cylinder, B. The feed nozzle is of rectangular cross-section, the outermost edge being tangent to the feed cylinder walls. Feed shims, C, may be attached to the innermost walls to adjust the open area of the feed nozzle available to entering pulp. The tangential injection of feed under pressure supports the vortex action of the pulp that has been detained in the cyclone; the centrifugal forces of this vortex throw the coarse particles to the walls of the cone, D, where they collect and pass downward and out through the adjustable apex opening, E. The fine particles contained in most of the water that entered with the feed pulp move to the inner spiral of the vortex and flow out through the vortex finder, F, contained in the orifice plate, G, which forms the top of cyclone chamber. The overflow pulp may then spray freely into a spray chamber, H, surmounting the cyclone or pass directly into a 90' elbow, I, of somewhat larger diameter than the vortex finder. Installation Where more than one cyclone is to be installed, best overall efficiency and ease of control are obtained with equal distribution of both pulp volume and weight of solids among the cyclones, and with the same pressure being maintained at each cyclone feed nozzle. Fig. 3 is a suggested arrangement for feeding two or more cyclones in parallel. Feed pressure control: Under normal operating conditions it is not unusual for some surge to exist in the feed that is to be sent to the cyclone. As will be discussed later, surges in the solids content of the pulp are usually not of great operational consequence, but surges in feed volume are a problem. Several systems have been devised for absorbing surges in feed volume, each involving a surge tank. If the surges are small and fairly rhythmical, a tank of sufficient size might be installed to dampen out

Jan 1, 1952

By Thomas Brownfield

The chronicle of the oil industry in Oklahoma in 1939 is one of declining production bolstered by strenuous efforts to find new pools or new producing horizons in the older, highly exploited, relatively shallow areas. Production, which averaged 608,000 bbl. daily in 1937, the post-depression peak, declined to 463,000 bbl. daily in 1938 and continued downward to 421,000 bbl. daily for the year 1939. While the state could produce somewhat more oil if demand warranted it, production in most areas is at as great a rate as could be justified on the basis of maximum efficient operation. Outlet for Oklahoma crude has been seriously affected by the increase in production in the Illinois Basin. Crude movements from the Kansas-Oklahoma area to the northeastern consuming centers averaged 314,000 bbl. daily in 1939 as compared with 397,000 bbl. in 1938. Oklahoma producers bore the brunt of this loss of market. The general production decline was accentuated by the August, shutdown of 15 days, precipitated by the action of a major crude purchaser posting a 20-cent reduction in the price of crude. The Oklahoma Corporation Commission, in collaboration with other members of the Interstate Oil Compact Commission, ordered a complete shutdown of all producing wells in order to prevent the premature abandonment of stripper wells, which might result from a prolonged period of production at prices below operating costs. The reduction in price was forestalled, most major purchasers failing to meet the cut in view of the shutdown, and the company initiating the move rescinded its action. Fear of the shutting in of oil wells, especially those making considerable quantities of water, is generally unfounded in the light of a superficial examination of the records. Oklahoma's unprorated pools, which produced 154,000 bbl. daily in May, declined to 152,000 bbl. in June and 143,000 bbl. in July. Immediately following the shutdown, the same pools produced 150,000 bbl. in September, 145,000 in October, and 145,-000 in November. Thus, while the half month's production loss in August has not been made up, the wells apparently hare produced at a greater rate since the shutdown than immediately preceding it.

Jan 1, 1940